gclog improvements

Rainer Jung rainer.jung at kippdata.de
Sun Oct 12 11:44:30 UTC 2008


as we all know, GC logging is still vital for finding a good sizing and
GC configuration.

Unfortunately the gclog gets overwrittten each time the JVM starts due
to the way the file gets opened. So in order to keep the files people
need to add rotation commands to their start scripts. Often this doesn't
happen and especially when emergency restarts where needed, the old
gclog is gone.

Any plans for changing this? Or maybe even adding log file rotation to
the gclog?

Furthermore: Until now there is no event based model of monitoring the
GC and Memory data. All methods apart from logging are based on a pull
model, that retrieves information in regular intervals. The most
important information does not exist in regular intervals, but instead
immediately after a GC. It would be nice to have some event based model
(e.g. like in JVMTI), that allows to track the same data as the gc
logging, without using the historically motivated gclog file format.

Thanks for your helpful and transparent comments on the mailing lists.



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